Laponite immobilized TiO2 catalysts for photocatalytic degradation of phenols

Erzsébet Décsiné Gombos, Dániel Krakkó, Gyula Záray, Ádám Illés, Sándor Dóbé, Ágnes Szegedi

Research output: Article

Abstract

Laponite immobilized titania catalysts were prepared by a pillaring process and by hydrothermal synthesis (HT) applying different titania sources such as TiCl4 and TiOSO4. Textural investigations (XRD, TEM, N2 physisorption) evidenced that by the pillaring procedure a high specific surface area (∼450 m2 g−1) mesoporous composite with 5–6 nm sized anatase nanoparticles were formed retaining the morphology of parent laponite structure. In contrast, by hydrothermal treatment with titanium oxysulfate the initial laponite structure was destroyed and a more opened nanoporous silica/titania material was formed with bigger, about 14 nm anatase particles. FT-IR spectroscopic investigations revealed the different acidic character of titania/Laponite composite samples showing stronger Lewis and weak Brönsted acid sites on both catalysts. However, acidic centers in titania pillared laponite stem from Ti–O–Si bonds, whereas in HT sample from the separated, ionic, surface sulfate species on titania. Catalytic activity of titania/Laponite composites were tested in photo-oxidation of model 10–5 M phenol and 2,4,6-trichlorophenol (TCP) water solutions. Catalytic tests were carried out in a home constructed batch-type photo-reactor with oxygen bubbling, and applying commercial low pressure Hg lamps emitting UV-light at 254 nm and 361 nm. Catalytic results showed that utilization of titania/Laponite catalysts enhanced the photo-oxidation activity. Hydrothermally prepared sample showed much better catalytic performance than titanium chloride pillared one, probably due to the bigger titania particles and the more opened mesoporous structure of titania/Laponite HT, and moreover to the peculiar surface acidic properties of sulfated titania species. Separation of catalysts from reaction media even in tap water was much easier than that of commercial titania, i.e. by self-settling.

Original languageEnglish
Article number112045
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume387
DOIs
Publication statusPublished - jan. 15 2020

Fingerprint

Titania
Photocatalysis
Phenols
Phenol
phenols
titanium
Titanium
degradation
catalysts
Degradation
Catalysts
Hydrothermal synthesis
photooxidation
Photooxidation
anatase
2,4,6-trichlorophenol
titanium dioxide
laponite
composite materials
Titanium dioxide

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

Cite this

Laponite immobilized TiO2 catalysts for photocatalytic degradation of phenols. / Décsiné Gombos, Erzsébet; Krakkó, Dániel; Záray, Gyula; Illés, Ádám; Dóbé, Sándor; Szegedi, Ágnes.

In: Journal of Photochemistry and Photobiology A: Chemistry, Vol. 387, 112045, 15.01.2020.

Research output: Article

@article{e275dff59b864cb2856b1c547c992dd5,
title = "Laponite immobilized TiO2 catalysts for photocatalytic degradation of phenols",
abstract = "Laponite immobilized titania catalysts were prepared by a pillaring process and by hydrothermal synthesis (HT) applying different titania sources such as TiCl4 and TiOSO4. Textural investigations (XRD, TEM, N2 physisorption) evidenced that by the pillaring procedure a high specific surface area (∼450 m2 g−1) mesoporous composite with 5–6 nm sized anatase nanoparticles were formed retaining the morphology of parent laponite structure. In contrast, by hydrothermal treatment with titanium oxysulfate the initial laponite structure was destroyed and a more opened nanoporous silica/titania material was formed with bigger, about 14 nm anatase particles. FT-IR spectroscopic investigations revealed the different acidic character of titania/Laponite composite samples showing stronger Lewis and weak Br{\"o}nsted acid sites on both catalysts. However, acidic centers in titania pillared laponite stem from Ti–O–Si bonds, whereas in HT sample from the separated, ionic, surface sulfate species on titania. Catalytic activity of titania/Laponite composites were tested in photo-oxidation of model 10–5 M phenol and 2,4,6-trichlorophenol (TCP) water solutions. Catalytic tests were carried out in a home constructed batch-type photo-reactor with oxygen bubbling, and applying commercial low pressure Hg lamps emitting UV-light at 254 nm and 361 nm. Catalytic results showed that utilization of titania/Laponite catalysts enhanced the photo-oxidation activity. Hydrothermally prepared sample showed much better catalytic performance than titanium chloride pillared one, probably due to the bigger titania particles and the more opened mesoporous structure of titania/Laponite HT, and moreover to the peculiar surface acidic properties of sulfated titania species. Separation of catalysts from reaction media even in tap water was much easier than that of commercial titania, i.e. by self-settling.",
keywords = "2,4,6-trichlorophenol, Laponite, Phenol, Photocatalysis, Titania",
author = "{D{\'e}csin{\'e} Gombos}, Erzs{\'e}bet and D{\'a}niel Krakk{\'o} and Gyula Z{\'a}ray and {\'A}d{\'a}m Ill{\'e}s and S{\'a}ndor D{\'o}b{\'e} and {\'A}gnes Szegedi",
year = "2020",
month = "1",
day = "15",
doi = "10.1016/j.jphotochem.2019.112045",
language = "English",
volume = "387",
journal = "Journal of Photochemistry and Photobiology A: Chemistry",
issn = "1010-6030",
publisher = "Elsevier",

}

TY - JOUR

T1 - Laponite immobilized TiO2 catalysts for photocatalytic degradation of phenols

AU - Décsiné Gombos, Erzsébet

AU - Krakkó, Dániel

AU - Záray, Gyula

AU - Illés, Ádám

AU - Dóbé, Sándor

AU - Szegedi, Ágnes

PY - 2020/1/15

Y1 - 2020/1/15

N2 - Laponite immobilized titania catalysts were prepared by a pillaring process and by hydrothermal synthesis (HT) applying different titania sources such as TiCl4 and TiOSO4. Textural investigations (XRD, TEM, N2 physisorption) evidenced that by the pillaring procedure a high specific surface area (∼450 m2 g−1) mesoporous composite with 5–6 nm sized anatase nanoparticles were formed retaining the morphology of parent laponite structure. In contrast, by hydrothermal treatment with titanium oxysulfate the initial laponite structure was destroyed and a more opened nanoporous silica/titania material was formed with bigger, about 14 nm anatase particles. FT-IR spectroscopic investigations revealed the different acidic character of titania/Laponite composite samples showing stronger Lewis and weak Brönsted acid sites on both catalysts. However, acidic centers in titania pillared laponite stem from Ti–O–Si bonds, whereas in HT sample from the separated, ionic, surface sulfate species on titania. Catalytic activity of titania/Laponite composites were tested in photo-oxidation of model 10–5 M phenol and 2,4,6-trichlorophenol (TCP) water solutions. Catalytic tests were carried out in a home constructed batch-type photo-reactor with oxygen bubbling, and applying commercial low pressure Hg lamps emitting UV-light at 254 nm and 361 nm. Catalytic results showed that utilization of titania/Laponite catalysts enhanced the photo-oxidation activity. Hydrothermally prepared sample showed much better catalytic performance than titanium chloride pillared one, probably due to the bigger titania particles and the more opened mesoporous structure of titania/Laponite HT, and moreover to the peculiar surface acidic properties of sulfated titania species. Separation of catalysts from reaction media even in tap water was much easier than that of commercial titania, i.e. by self-settling.

AB - Laponite immobilized titania catalysts were prepared by a pillaring process and by hydrothermal synthesis (HT) applying different titania sources such as TiCl4 and TiOSO4. Textural investigations (XRD, TEM, N2 physisorption) evidenced that by the pillaring procedure a high specific surface area (∼450 m2 g−1) mesoporous composite with 5–6 nm sized anatase nanoparticles were formed retaining the morphology of parent laponite structure. In contrast, by hydrothermal treatment with titanium oxysulfate the initial laponite structure was destroyed and a more opened nanoporous silica/titania material was formed with bigger, about 14 nm anatase particles. FT-IR spectroscopic investigations revealed the different acidic character of titania/Laponite composite samples showing stronger Lewis and weak Brönsted acid sites on both catalysts. However, acidic centers in titania pillared laponite stem from Ti–O–Si bonds, whereas in HT sample from the separated, ionic, surface sulfate species on titania. Catalytic activity of titania/Laponite composites were tested in photo-oxidation of model 10–5 M phenol and 2,4,6-trichlorophenol (TCP) water solutions. Catalytic tests were carried out in a home constructed batch-type photo-reactor with oxygen bubbling, and applying commercial low pressure Hg lamps emitting UV-light at 254 nm and 361 nm. Catalytic results showed that utilization of titania/Laponite catalysts enhanced the photo-oxidation activity. Hydrothermally prepared sample showed much better catalytic performance than titanium chloride pillared one, probably due to the bigger titania particles and the more opened mesoporous structure of titania/Laponite HT, and moreover to the peculiar surface acidic properties of sulfated titania species. Separation of catalysts from reaction media even in tap water was much easier than that of commercial titania, i.e. by self-settling.

KW - 2,4,6-trichlorophenol

KW - Laponite

KW - Phenol

KW - Photocatalysis

KW - Titania

UR - http://www.scopus.com/inward/record.url?scp=85073416419&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85073416419&partnerID=8YFLogxK

U2 - 10.1016/j.jphotochem.2019.112045

DO - 10.1016/j.jphotochem.2019.112045

M3 - Article

AN - SCOPUS:85073416419

VL - 387

JO - Journal of Photochemistry and Photobiology A: Chemistry

JF - Journal of Photochemistry and Photobiology A: Chemistry

SN - 1010-6030

M1 - 112045

ER -